Cryosurgical probes are used to treat a variety of diseases. Cryosurgical probes quickly freeze diseased body tissue, causing the tissue to die after which it will be absorbed by the body, expelled by the body, sloughed off or replaced by scar tissue. Cryothermal treatment can be used to treat prostate cancer and benign prostate disease. Cryosurgery also has gynecological applications. In addition, cryosurgery may be used for the treatment of a number of other diseases and conditions including breast cancer, liver cancer, glaucoma and other eye diseases.
A variety of cryosurgical instruments variously referred to as cryoprobes, cryosurgical probes, cryosurgical ablation devices, cryostats and cryocoolers have been used for cryosurgery. These devices typically use the principle of Joule-Thomson expansion to generate cooling. They take advantage of the fact that most fluids, when rapidly expanded, become extremely cold. In these devices, a high pressure gas mixture is expanded through a nozzle inside a small cylindrical shaft or sheath typically made of steel. The Joule-Thomson expansion cools the steel sheath to a cold temperature very rapidly. The cryosurgical probes then form ice balls which freeze diseased tissue without undue destruction of surrounding healthy tissue.
Cryosurgery often involves a cycle of treatments in which the targeted tissue is frozen, allowed to thaw and then refrozen. Double and even triple thaw cycles are now commonly performed. Comparison with single freeze thaw cycle shows that the second freeze will increase damage to the diseased tissue and thus the efficiency of the treatment.
A typical cryosurgical probe will include one or more auxiliary instruments near the cold tip. Such instruments include electrical heaters and temperature sensors. Frequently the cold tip must be interchangeable with various shapes, dimensions, and edges so as to perform different surgical procedures. Moreover, there is a need to that the probe be capable of sterilization for repeated surgical procedures. Thus there is a need for a disposable compact sheath with integrated capabilities for the auxiliary equipment, and a coupling system for facilitating probe end replacement when necessary.